fix(stats): repair stale KOReader file identities

Recompute the open file digest and recover previously verified matches without guessing between duplicate files. Preserve stranded statistics across lifecycle retries and advertise plugin version 1.5.3 so installed devices can update.

Fixes #1497

koreader-plugin/bookorbit.koplugin/bookorbit_state.lua

@@ -166,6 +166,34 @@ function BookOrbitState:rememberFile(file, md5)
     end
 end
 
+-- Repairs a path whose cached digest no longer matches the file on disk. A
+-- server identity is never copied between digests: only an identity already
+-- verified for the recomputed digest may be used to recover an ambiguous
+-- server match.
+function BookOrbitState:repairFileIdentity(file, old_md5, new_md5)
+    if not file or not new_md5 then return nil end
+    self.files[file] = new_md5
+
+    if old_md5 and old_md5 ~= new_md5 then
+        local old_book = self.books[old_md5]
+        if old_book and old_book.file == file then
+            old_book.file = nil
+            BookOrbitState.expireMatch(old_book)
+        end
+        self.unmatched[new_md5] = nil
+    end
+
+    local new_book = self.books[new_md5]
+    if new_book then
+        new_book.file = file
+        if old_md5 ~= new_md5 then
+            BookOrbitState.expireMatch(new_book)
+            new_book.statsWatermark = 0
+        end
+    end
+    return new_book
+end
+
 function BookOrbitState:flush()
     if self.flush_handler then
         return self.flush_handler(self)